Maximum Input Capacity (BTU)
The Maximum Input Capacity describes how quickly the appliance will use fuel when delivering it's maximum capacity. The units may change depending on the fuel being used.

154000 - 157999 (4)

158000 - 161999 (22)

174000 - 177999 (1)

178000 - 181999 (42)

190000 - 193999 (13)

198000+ (30)

AFUE (%)
AFUE (Annual Fuel Utilization Efficiency) measures the efficiency of combustion equipment over the entire heating season, and is calculated by dividing the amount of energy that is actually heating your home by the total energy contained in the fuel used by the boiler/furnace. Learn More

82 (1)

84 (1)

88 (2)

Efficiency (%)

84 (1)

97 (4)

Vent Type
Products that use combustion (burning) of fuel to create heat also create potentially dangerous gasses that need to be exhausted (AKA "Vented"). Depending on the product, venting can be done via a chimney, through a side wall, or use a second vent to provide fresh air to the appliance.

Concentric Vent (7)

Direct Vent (55)

Outdoor (No Venting) (48)

Power Vent (2)

Fuel Type
To create heat, some form of fuel is required. Fuel Type specifies what the product uses as an input to create heat.

Liquid Propane (51)

Natural Gas (61)

Flow Rate at 40F Temperature Rise (GPM)
Flow rate measures how much hot water your heater can deliver. Click Learn More to determine the appropriate temperature rise to use based on your location. Learn More

6 (8)

7 (45)

8 (59)

Flow Rate at 50F Temperature Rise (GPM)
Flow rate measures how much hot water your heater can deliver. Click Learn More to determine the appropriate temperature rise to use based on your location. Learn More

5 (7)

6 (103)

7 (2)

Flow Rate at 60F Temperature Rise (GPM)
Flow rate measures how much hot water your heater can deliver. Click Learn More to determine the appropriate temperature rise to use based on your location. Learn More